How bad is it to learn from a Top Chef Master that you've never in your life held a knife correctly? We're in the kitchen at Rick Moonen's 330-pax RM Seafood restaurant in Mandalay Bay, Las Vegas for his sushi seminar. He's enlightening us on the pitfalls of farmed fish—Rick's a guru of sustainable seafood—while building delicate and delish California rolls. Make that sustainable California rolls. When the celeb chef sliced mine because he feared for my fingers, I chalked it up to good teambuilding and happily took my photo op.

Sustainable seafood in a 3,200-room hotel in the Nevada desert? You bet. Moonen's hipster eco-ethics have helped win the property five Keys from the Green Key global eco-rating program, an honor bestowed on just six resorts worldwide. A recent room redo contributed water-saving plumbing in bathrooms the size of New York apartments, smart thermostats, and gorgeous low-VOC paint and carpets. (Props to owner MGM/Mirage, whose total enviro-savings could power 5,500 homes a year.) The Shark Reef Aquarium, where 2,000 aquatic predators star at 50-1,500 events attended by 50 to 1,500 guests, including diving-with-sharks parties, is internationally respected for its conservation and educational efforts.

Darel Cook, Director of Expositions for the Promotional Products Association, held his first-ever event here in 2003 and returns every year.

"There's not another place like this—a real convention center with a hotel feel," says Cook, happily supervising 20,000 guests at his 2011 Expo. "We never have to market the destination because Mandalay Bay is so upscale. We focus on our event." Judging from the crowd, the focus paid off.

Not all confabs are so big, explains COO Chuck Bowling. "Sure, we like big groups, but 65% are under 300."

They seem to leave happy, yes?

Bowling laughs. "In the city that is an entertainment capital, our hotel is the entertainment capital—always something new."

He begins ticking off: Aureole was renovated to show off the "wine angels"—gorgeous acrobats who retrieve bottles from a four-story wine tower; Ri Ra, the first Guinness store outside of Ireland, opened St. Patrick's Day; and the American debut of Cirque de Soleil's Michael Jackson the Immortal. Bowling grins. "That will be the most talked about event for a long time."

Over at The Mirage, I have to smile like a kid at the gold-tinted windows, a 53-foot lobby aquarium, and outside, a smoking volcano with 150 fireball-throwing machines choreographed to a drumbeat symphony. The hotel's tagline is: "Erupting Nightly."

"The Mirage was a game-changer," says Sandy Zanella, PR Director for MGM/Mirage, over martinis and meatballs at the stylish Onda Restaurant & Wine Lounge. "It's the first mega-resort built for entertainment and gaming." Two decades later, Mirage has invested $80 million to keep 3,044 rooms and 170,000-sf function space wonderfully comfy.

Our food was so very-Vegas that we had to meet Exec Chef Jeff Braun. "Diners go for my Rat Pack menus with caviar, beef tenderloin and seafood martinis," he says. An Italophile, Braun's antipasto includes lardo—an ancient delicacy of cured pork fat.

Later, Sandy slipped us into the once-secret mini-kingdoms called The Villas at the Mirage. As we gasped at the 3,400-sf two-bedroom haciendas full of plush furniture, art and satellite TVs, Sandy explained, "These aren't just for rock stars and high-rollers anymore." After counting five bathrooms and multiple party rooms, we stepped out for a final pinch-me moment: private pool, hot tub, fountain and a putting green. Time to go high-rollin'...